Housings made of composite materials have many advantages, including especially their weight reduced in comparison to equivalent metallic housings. Such housings can especially be made of composite material comprising for example a fibrous reinforcement densified by a matrix. The fibrous reinforcement can be formed by a winding in layers superposed on a mandrel of a fibrous texture obtained by three-dimensional weaving with evolutive thickness, to integrate the retention shield by simple localised increase in thickness.
Yet, since the matrix of these composite materials generally comprises material polymer such as resin, they exhibit major electrical resistance and therefore do not adequately conduct electricity to correctly evacuate electric power. However, the electrical equipment of the housing can be subject to an aggressive electromagnetic environment (especially to high-intensity radiated fields (or HIRF), lightning strikes, electromagnetic interference (EMI), etc., in which they must be capable of functioning nominally.
The result is considerable risk of damaging the equipment of the engine, such as the ignition box, or even mechanical equipment through which for example large quantities of oil or fuel pass.
Also, when electrical energy cannot be evacuated, it causes a substantial rise in temperature of the housing by joule effect. Composite materials used to make the fan retention housings are limited to a use temperature of generally under a hundred degrees. If this temperature is exceeded, the housing risks melting at least locally or burning (combustion) and no longer being able to support all or some of the electrical equipment which they support.
Also, in the event where the housing made of insulating material is an OFD housing, the latter is connected at the level of its downstream end to a thrust reverser. To evacuate electrical energy from the thrust reverser, it has been proposed to create a primary connecting path between the thrust reverser and the pylon of the aircraft. However, the applicant has noticed that this evacuation of electrical energy via this primary path was inadequate relative to the loads to be transited.
Document US 2013/189868 describes an engine comprising a housing and equipment fixed to the housing, as well as an electrically conductive connecting path for connecting the equipment to a metallic structure to evacuate electrons.
Document FR 2 933 378 per se describes mounting an antenna on an aircraft to produce and ensure metallisation of the antenna by its fastening bolts, including when the skin of the aircraft is made of composite material, by means a metallic socket connected electrically to the earth of the aircraft.